// Copyright 2023 Huawei Cloud Computing Technology Co., Ltd.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

import logger from '../Logger';
const Logger = logger;

export class Events {
  eventsQueue = {};
  target = {};
  disallowRepeat = false;
  constructor(target) {
    this.target = target;
  }

  add(types = [], fn, once) {
    for (let type of types) {
      this.on(type, fn, once);
    }
  }

  on(type, fn, once) {
    if (this.eventsQueue[type] === undefined) {
      this.eventsQueue[type] = { methods: [], once: false };
    }
    if (typeof fn !== 'function') {
      Logger.error('on', 'the argument is not function.', fn);
      return;
    }
    // disallow repeat bind
    if (this.disallowRepeat && this.eventsQueue[type]['methods'].includes(fn)) {
      return;
    }
    this.eventsQueue[type].methods.push(fn);
    if (once !== undefined) {
      this.eventsQueue[type].once = once;
    }
    return this.target;
  }

  once(type, fn) {
    this.on(type, fn, true);
  }
  /**
   *
   * @param {string} type
   * @param {Function} [fn] be removed function, default all
   */
  off(type, fn) {
    let event = this.eventsQueue[type];
    if (!event) {
      return;
    }
    let methods = event.methods;
    if (!fn) {
      delete this.eventsQueue[type];
    } else {
      let len = methods.length;
      while (len--) {
        if (methods[len] === fn) {
          methods.splice(len, 1);
        }
      }
    }
    return this.target;
  }

  emit(type, ...args) {
    let event = this.eventsQueue[type];
    if (!event) {
      return;
    }
    let methods = event.methods;
    methods.forEach((method) => {
      method.apply(this.target, args);
    });
    // remove the event after first called
    if (event.once) {
      this.off(type);
    }
    return this.target;
  }

  clear(type) {
    delete this.eventsQueue[type];
  }

  clearAll() {
    this.eventsQueue = {};
  }
}

export const events = (obj) => {
  return new Events(obj);
};

const getEvents = function (obj) {
  const instance = new Events(obj);
  return (obj) => {
    instance.target = obj;
    return instance;
  };
};

export default getEvents;
